diff --git a/satrs/src/lib.rs b/satrs/src/lib.rs
index c31df8d..ae9122c 100644
--- a/satrs/src/lib.rs
+++ b/satrs/src/lib.rs
@@ -34,6 +34,7 @@ pub mod events;
 #[cfg_attr(doc_cfg, doc(cfg(feature = "std")))]
 pub mod executable;
 pub mod hal;
+pub mod mode_tree;
 pub mod objects;
 pub mod pool;
 pub mod power;
@@ -51,8 +52,7 @@ pub mod params;
 
 pub use spacepackets;
 
-/// Generic channel ID type.
-pub type ChannelId = u32;
+pub use queue::ChannelId;
 
 /// Generic target ID type.
 pub type TargetId = u64;
diff --git a/satrs/src/mode.rs b/satrs/src/mode.rs
index c5968b4..1346226 100644
--- a/satrs/src/mode.rs
+++ b/satrs/src/mode.rs
@@ -5,19 +5,22 @@ use spacepackets::ByteConversionError;
 
 use crate::TargetId;
 
+pub type Mode = u32;
+pub type Submode = u16;
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct ModeAndSubmode {
-    mode: u32,
-    submode: u16,
+    mode: Mode,
+    submode: Submode,
 }
 
 impl ModeAndSubmode {
-    pub const fn new_mode_only(mode: u32) -> Self {
+    pub const fn new_mode_only(mode: Mode) -> Self {
         Self { mode, submode: 0 }
     }
 
-    pub const fn new(mode: u32, submode: u16) -> Self {
+    pub const fn new(mode: Mode, submode: Submode) -> Self {
         Self { mode, submode }
     }
 
@@ -33,16 +36,20 @@ impl ModeAndSubmode {
             });
         }
         Ok(Self {
-            mode: u32::from_be_bytes(buf[0..4].try_into().unwrap()),
-            submode: u16::from_be_bytes(buf[4..6].try_into().unwrap()),
+            mode: Mode::from_be_bytes(buf[0..size_of::<Mode>()].try_into().unwrap()),
+            submode: Submode::from_be_bytes(
+                buf[size_of::<Mode>()..size_of::<Mode>() + size_of::<Submode>()]
+                    .try_into()
+                    .unwrap(),
+            ),
         })
     }
 
-    pub fn mode(&self) -> u32 {
+    pub fn mode(&self) -> Mode {
         self.mode
     }
 
-    pub fn submode(&self) -> u16 {
+    pub fn submode(&self) -> Submode {
         self.submode
     }
 }
@@ -87,6 +94,20 @@ pub enum ModeRequest {
     AnnounceModeRecursive,
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum ModeReply {
+    /// Unrequest mode information. Can be used to notify other components of changed modes.
+    ModeInfo(ModeAndSubmode),
+    /// Reply to a mode request to confirm the commanded mode was reached.
+    ModeReply(ModeAndSubmode),
+    CantReachMode(ModeAndSubmode),
+    WrongMode {
+        expected: ModeAndSubmode,
+        reached: ModeAndSubmode,
+    },
+}
+
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct TargetedModeRequest {
diff --git a/satrs/src/mode_tree.rs b/satrs/src/mode_tree.rs
new file mode 100644
index 0000000..4eaecf6
--- /dev/null
+++ b/satrs/src/mode_tree.rs
@@ -0,0 +1,261 @@
+use std::sync::mpsc;
+
+use alloc::vec::Vec;
+use hashbrown::HashMap;
+
+use crate::{
+    mode::{Mode, ModeAndSubmode, ModeReply, ModeRequest, Submode},
+    queue::GenericSendError,
+    ChannelId,
+};
+
+pub struct ModeRequestWithSenderId {
+    pub sender_id: ChannelId,
+    pub request: ModeRequest,
+}
+
+impl ModeRequestWithSenderId {
+    pub fn new(sender_id: ChannelId, request: ModeRequest) -> Self {
+        Self { sender_id, request }
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum TableEntryType {
+    /// Target table containing information of the expected children modes for  given mode.
+    Target,
+    /// Sequence table which contains information about how to reach a target table, including
+    /// the order of the sequences.
+    Sequence,
+}
+
+pub struct ModeTableEntry {
+    /// Name of respective table entry.
+    pub name: &'static str,
+    /// Target channel ID.
+    pub channel_id: ChannelId,
+    pub mode_submode: ModeAndSubmode,
+    pub allowed_submode_mask: Option<Submode>,
+    pub check_success: bool,
+}
+
+pub struct ModeTableMapValue {
+    /// Name for a given mode table entry.
+    pub name: &'static str,
+    pub entries: Vec<ModeTableEntry>,
+}
+
+pub type ModeTable = HashMap<Mode, ModeTableMapValue>;
+
+#[derive(Debug, Clone)]
+pub enum ModeMessagingError {
+    TargetDoesNotExist(ChannelId),
+    Send(GenericSendError),
+}
+impl From<GenericSendError> for ModeMessagingError {
+    fn from(value: GenericSendError) -> Self {
+        Self::Send(value)
+    }
+}
+
+pub trait ModeReplyHandler {
+    fn local_channel_id(&self) -> ChannelId;
+
+    fn send_mode_reply(
+        &mut self,
+        target_id: ChannelId,
+        reply: ModeReply,
+    ) -> Result<(), ModeMessagingError>;
+}
+
+pub struct StandardModeReplyMap {
+    pub local_id: ChannelId,
+    pub reply_sender_map: HashMap<ChannelId, mpsc::Sender<ModeReply>>,
+}
+
+impl ModeReplyHandler for StandardModeReplyMap {
+    fn send_mode_reply(
+        &mut self,
+        target_channel_id: ChannelId,
+        reply: ModeReply,
+    ) -> Result<(), ModeMessagingError> {
+        if self.reply_sender_map.contains_key(&target_channel_id) {
+            self.reply_sender_map
+                .get(&target_channel_id)
+                .unwrap()
+                .send(reply)
+                .map_err(|_| GenericSendError::RxDisconnected)?;
+            return Ok(());
+        }
+        Err(ModeMessagingError::TargetDoesNotExist(target_channel_id))
+    }
+
+    fn local_channel_id(&self) -> ChannelId {
+        self.local_id
+    }
+}
+
+pub trait ModeRequestSender {
+    fn local_channel_id(&self) -> Option<ChannelId>;
+    fn send_mode_request(
+        &mut self,
+        target_id: ChannelId,
+        request: ModeRequest,
+    ) -> Result<(), ModeMessagingError>;
+}
+
+pub struct StandardModeRequestMap {
+    pub local_channel_id: ChannelId,
+    pub request_sender_map: HashMap<ChannelId, mpsc::Sender<ModeRequestWithSenderId>>,
+}
+
+impl ModeRequestSender for StandardModeRequestMap {
+    fn send_mode_request(
+        &mut self,
+        target_id: ChannelId,
+        request: ModeRequest,
+    ) -> Result<(), ModeMessagingError> {
+        if self.request_sender_map.contains_key(&target_id) {
+            self.request_sender_map
+                .get(&target_id)
+                .unwrap()
+                .send(ModeRequestWithSenderId {
+                    sender_id: target_id,
+                    request,
+                })
+                .map_err(|_| GenericSendError::RxDisconnected)?;
+            return Ok(());
+        }
+        Err(ModeMessagingError::TargetDoesNotExist(target_id))
+    }
+
+    fn local_channel_id(&self) -> Option<ChannelId> {
+        Some(self.local_channel_id)
+    }
+}
+
+pub trait ModeProvider {
+    fn mode_and_submode(&self) -> ModeAndSubmode;
+}
+
+#[derive(Debug, Clone)]
+pub enum ModeError {
+    Messaging(ModeMessagingError),
+}
+
+pub trait ModeRequestHandler: ModeProvider {
+    fn start_transition(&mut self, mode_and_submode: ModeAndSubmode) -> Result<(), ModeError>;
+
+    fn announce_mode(&self, recursive: bool);
+    fn handle_mode_reached(&mut self) -> Result<(), ModeMessagingError>;
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{println, sync::mpsc};
+
+    use crate::{
+        mode::{ModeAndSubmode, ModeReply, ModeRequest},
+        mode_tree::ModeRequestSender,
+        ChannelId,
+    };
+
+    use super::{
+        ModeMessagingError, ModeProvider, ModeReplyHandler, ModeRequestHandler,
+        ModeRequestWithSenderId, StandardModeReplyMap, StandardModeRequestMap,
+    };
+
+    struct TestDevice {
+        /// One receiver handle for all mode requests.
+        pub mode_req_receiver: mpsc::Receiver<ModeRequestWithSenderId>,
+        /// This structure contains all handles to send mode replies.
+        pub mode_reply_sender: StandardModeReplyMap,
+        pub last_mode_sender: Option<ChannelId>,
+        pub mode_and_submode: ModeAndSubmode,
+        pub target_mode_and_submode: Option<ModeAndSubmode>,
+    }
+
+    struct TestAssembly {
+        /// One receiver handle for all mode requests.
+        pub mode_req_receiver: mpsc::Receiver<ModeRequestWithSenderId>,
+        /// This structure contains all handles to send mode replies.
+        pub mode_reply_sender: StandardModeReplyMap,
+        /// This structure contains all handles to send mode requests to its children.
+        pub mode_children_map: StandardModeRequestMap,
+        pub last_mode_sender: Option<ChannelId>,
+        pub mode_and_submode: ModeAndSubmode,
+        pub target_mode_and_submode: Option<ModeAndSubmode>,
+    }
+
+    impl ModeProvider for TestAssembly {
+        fn mode_and_submode(&self) -> ModeAndSubmode {
+            self.mode_and_submode
+        }
+    }
+
+    impl TestAssembly {
+        pub fn check_mode_requests(&mut self) {
+            match self.mode_req_receiver.try_recv() {
+                Ok(ModeRequestWithSenderId { sender_id, request }) => {
+                    match request {
+                        ModeRequest::SetMode(mode_and_submode) => {
+                            self.start_transition(mode_and_submode).unwrap();
+                            self.last_mode_sender = Some(sender_id);
+                        }
+                        ModeRequest::ReadMode => {
+                            // self.handle_read_mode_request(0, self.mode_and_submode, &mut self.mode_reply_sender).unwrap()
+                            self.mode_reply_sender
+                                .send_mode_reply(
+                                    sender_id,
+                                    ModeReply::ModeReply(self.mode_and_submode),
+                                )
+                                .unwrap()
+                        }
+                        ModeRequest::AnnounceMode => self.announce_mode(false),
+                        ModeRequest::AnnounceModeRecursive => self.announce_mode(true),
+                    }
+                }
+                Err(_) => todo!(),
+            };
+        }
+    }
+    impl ModeRequestHandler for TestAssembly {
+        fn start_transition(
+            &mut self,
+            mode_and_submode: ModeAndSubmode,
+        ) -> Result<(), super::ModeError> {
+            self.target_mode_and_submode = Some(mode_and_submode);
+            Ok(())
+        }
+
+        fn announce_mode(&self, recursive: bool) {
+            println!(
+                "Announcing mode (recursively: {}): {:?}",
+                recursive, self.mode_and_submode
+            );
+            let mut mode_request = ModeRequest::AnnounceMode;
+            if recursive {
+                mode_request = ModeRequest::AnnounceModeRecursive;
+            }
+            self.mode_children_map
+                .request_sender_map
+                .iter()
+                .for_each(|(_, sender)| {
+                    sender
+                        .send(ModeRequestWithSenderId::new(
+                            self.mode_children_map.local_channel_id().unwrap(),
+                            mode_request,
+                        ))
+                        .expect("sending mode request failed");
+                });
+        }
+
+        fn handle_mode_reached(&mut self) -> Result<(), ModeMessagingError> {
+            self.mode_reply_sender.send_mode_reply(
+                self.last_mode_sender.unwrap(),
+                ModeReply::ModeReply(self.mode_and_submode),
+            )?;
+            Ok(())
+        }
+    }
+}
diff --git a/satrs/src/queue.rs b/satrs/src/queue.rs
index 25ff6c6..2d344e0 100644
--- a/satrs/src/queue.rs
+++ b/satrs/src/queue.rs
@@ -2,6 +2,9 @@ use core::fmt::{Display, Formatter};
 #[cfg(feature = "std")]
 use std::error::Error;
 
+/// Generic channel ID type.
+pub type ChannelId = u32;
+
 /// Generic error type for sending something via a message queue.
 #[derive(Debug, Copy, Clone)]
 pub enum GenericSendError {